Download Overview Do you have a client who has been diagnosed with

Overview
Do you have a client who has been diagnosed with
glaucoma? Do you wonder what this diagnosis means?
Glaucoma affects tens of millions of people worldwide.
Despite its prevalence, many people lack accurate
information about this disease. The goal of this course is
to provide glaucoma-related information that can help you
take a supportive role during your client's adjustment to life
with glaucoma.
This course consists of five lessons. Lesson 1 discusses
the human eye and several forms of glaucoma. Lesson 2
explains how glaucoma is diagnosed. Lesson 3 describes
treatments for this disease. Lesson 4 discusses the
emotional impact of the visual impairment that results if
glaucoma is not diagnosed and treated. And finally,
Lesson 5 explains ways to continue daily activities if vision
loss occurs. The material in this course is informational
only; it constitutes neither the advice of a medical doctor
nor that of a rehabilitation specialist or professionals who
are qualified to diagnose and treat glaucoma and any
resulting visual impairment.
Overview
i
For your convenience, some lessons begin with a list of
key terms to introduce and define words that may be
unfamiliar. Each lesson also includes section reviews. The
section reviews in the lessons are for your personal
development only. Do not send your answers to your
Hadley instructor. You can always contact your instructor,
however, to either clarify these activities or discuss your
work. Students who routinely complete the section reviews
perform significantly better on assignments.
To complete this course you are required to submit five
assignments, one at the end of each lesson. These
assignments enable your instructor to assess your
mastery of the material in the lessons. Refer to the Getting
Started instructions for information about how to prepare
and submit assignments.
To personalize the course, some assignment questions
ask you to apply material in a lesson to you or your client.
In responding to such questions, include only information
that you are comfortable revealing. Moreover, if applicable,
to respect your client’s privacy, do not identify them by full
name in any assignment.
Overview
ii
If you are ready to learn about glaucoma, begin Lesson 1:
What Is Glaucoma?
Overview
iii
Overview
iv
Lesson 1: What Is Glaucoma?
Glaucoma is an eye disease that causes damage to the
optic nerve and loss of peripheral (outer) vision. Elevated
eye pressure is also usually present. If left undiagnosed
and untreated, glaucoma can result in blindness.
Glaucoma occurs most often in people over the age of 40,
but it can also affect infants, children, and young adults.
What does it mean to have glaucoma? What puts a
person at risk of developing this disease?
Lesson 1 explains the workings of a healthy eye. It also
describes the progression and risk factors for glaucoma.
First, the lesson discusses primary open-angle glaucoma,
the most common form of the disease. Then it discusses
some less common forms, including normal-tension
glaucoma, closed-angle glaucoma, congenital glaucoma,
and secondary glaucoma. Recognizing glaucoma helps
you take a supportive role during your client's adjustment
to life with glaucoma.
Lesson 1: What is Glaucoma?
1
Objectives
After completing this lesson, you will be able to
a. list the parts of an eye and describe their functions
b. describe primary open-angle glaucoma
c. describe several other forms of glaucoma
Key Terms
The following terms appear in this lesson. Familiarize
yourself with their meanings so that you can use them in
your course work.
anterior chamber: front compartment of the eye that is
filled with a clear watery fluid and is surrounded by
the cornea, iris, lens, and pupil
aqueous humor: clear watery fluid that fills the anterior
and posterior chambers of the eye; nourishes eye
tissue
ciliary body: tissue that is located behind the iris and that
produces the aqueous humor
closed-angle glaucoma (CAG): an eye disease in which
the space called the “angle” between the iris and the
cornea is narrowed or blocked. The aqueous humor
then cannot drain from the eye, causing an increase
in pressure within the eye.
Lesson 1: What is Glaucoma?
2
cornea: clear tissue that covers the front of the eye and
through which rays of light enter the eye
intraocular pressure (IOP): pressure inside the eye
iridocorneal endothelial syndrome (ICE): a condition
that is caused by the cornea adhering to the iris and
blocking the drainage of aqueous humor from the eye
iris: thin membrane that gives the eye its color; muscles in
the iris allow changes in the size of the pupil
lens: part of the eye that is located behind the iris and that
focuses light onto the retina
normal-tension glaucoma (NTG): a form of glaucoma in
which damage occurs to the optic nerve without eye
pressure exceeding the normal range
optic disc: located in the retina, it is the site where nerve
fibers from the retina come together to form the optic
nerve
optic nerve: bundle of nerve fibers that is located at the
back of the eye that carries electrical impulses from
the retina to the brain
posterior chamber: part of the eye that is behind the
anterior chamber, between the iris and the lens, and
is filled with aqueous fluid
Lesson 1: What is Glaucoma?
3
primary open-angle glaucoma (POAG): an eye disease
that causes damage to the optic nerve as a result of
the slower-than-normal exit of aqueous humor
through the eye’s normal drainage channel
pupil: opening in the center of the iris through which light
passes; in normal eyes, it appears as a dark circle
retina: innermost layer of the eye; converts light energy
into electrical impulses, which are sent to the brain
through the optic nerve
Schlemm’s canal: a draining channel that is located
below the trabecular meshwork and that carries
aqueous humor away from the eye
sclera: a thin yet tough protective shell that surrounds the
eye and is commonly called the white of the eye
trabecular meshwork: the part of the “angle” of the eye
located between the iris and the cornea; aqueous
humor passes through this tissue as it exits the eye
uveoscleral pathway: minor pathway that allows
aqueous humor to exit the eye through the sclera
The Healthy Eye
This section describes the human eye and how it works.
This information will give you a better understanding of
Lesson 1: What is Glaucoma?
4
glaucoma and its effect on vision. It will also provide you
with the vocabulary necessary for discussing this disease.
Note, however, that this is not an in-depth study of the
eye. Such detail is beyond the scope of this course. To
start the reading, select the Next button below. Once you
have completed the reading, continue to the section
review.
How does a person see? Rays of light pass through the
cornea and aqueous fluid, and enter through the pupil and
lens. The light passes through the space in the back of the
eye that is filled with a gel called the vitreous, and the light
then hits the retina. In the retina light energy is converted
to electrical energy that is sent to the brain through the
optic nerve. The brain interprets the received electrical
energy as vision.
Now consider this process in terms of parts of the eye. To
start, the sclera is a thin yet very strong protective shell
that surrounds the eye and is commonly known as the
white of the eye. The cornea, the clear tissue through
which light enters the eye, bends the rays of light, which
then pass through the anterior, or front, chamber of the
inner eye.
Lesson 1: What is Glaucoma?
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The cornea, iris, lens, and pupil surround this chamber,
which contains the fluid called aqueous humor. In the back
of the anterior chamber is the iris, a thin membrane that
gives the eye its color. The opening in the center of the iris
is called the pupil, and it appears as a dark circle. By
controlling the size of the pupil, the iris regulates the
amount of light that reaches the retina.
Light passes through the pupil and the lens, which is
located behind the iris. The lens focuses incoming light
onto the retina, the innermost part of the eye. The retina
converts the light energy into electrical impulses, which
are sent to the brain through the optic nerve. Finally, the
brain interprets these impulses as images that a person
sees. The optic nerve consists of more than one million
nerve fibers, all of which originate in the retina. The place
in the back of the eye where the fibers come together to
form the optic nerve is called the optic disc.
A few additional parts of the eye are relevant to the study
of glaucoma. The ciliary body, located behind the iris,
produces the fluid called aqueous humor. Aqueous humor
flows into the posterior chamber, which is located between
the lens and iris and then passes through the pupil into the
Lesson 1: What is Glaucoma?
6
anterior chamber. This fluid nourishes eye tissue, and its
presence helps maintain the shape of the eye. This
pressure is called intraocular pressure (IOP). Normally,
the volume of fluid produced by the ciliary body within the
eye is the same as the amount of fluid leaving the eye.
This balance of production and exit of aqueous fluid
creates a normal IOP that is between 12 and 21
millimeters of mercury (mmHg).
For the most part, aqueous humor leaves the eye after
passing through the trabecular meshwork, a tissue located
between the cornea and the iris. After passing through the
meshwork, the fluid enters the Schlemm’s canal, a
structure that functions like a pipe or drain to transport the
fluid away from the eye. In addition, the uveoscleral
pathway is a minor route for aqueous humor outflow. In
this case, the fluid passes through small channels in the
sclera.
Now study the following diagram of the human eye.
Although basic, it includes most of the eye parts
mentioned in this discussion.
Lesson 1: What is Glaucoma?
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Figure 1-1: Eye Diagram
Credit: Adapted from illustration NEA08, courtesy of National Eye
Institute, National Institutes of Health
Section Review
Review the information in this section by answering the
following true/false and multiple-choice questions. Use the
Check Answer button to get the correct answer and an
explanation.
Lesson 1: What is Glaucoma?
8
True/False
Indicate whether the following statements are true or false.
Note that inadvertent keystrokes may change your
answers.
1. The sclera is known as the white of the eye.
Correct! The statement is true. The sclera is known as
the white of the eye.
2. Fluid leaves the eye through only one route.
Correct! The statement is false. Fluid leaves the eye
through the trabecular meshwork and the Schlemm’s
canal and to a lesser extent, through the uveoscleral
pathway.
3. The pupil controls the size of the iris.
Correct! The statement is false. The iris controls the
size of the pupil.
Lesson 1: What is Glaucoma?
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4. The optic nerve consists of more than one million
nerve fibers.
Correct! The statement is true. The optic nerve
consists of more than one million nerve fibers.
Multiple Choice
Select the best answer for each of the following items.
Note that inadvertent keystrokes may change your
answers.
5. Which part of the eye produces aqueous humor?
a. retina
b. cornea
c.
d.
ciliary body
optic nerve
Correct! The answer is (c). The ciliary body produces
aqueous humor.
6. Which of the following is the clear tissue that covers
the front of the eye?
a. retina
b. optic nerve
c. ciliary body
Lesson 1: What is Glaucoma?
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d.
cornea
Correct! The answer is (d). The cornea is the clear
tissue that covers the front of the eye.
7. Which of the following is the thin membrane that gives
the eye its color?
a.
b.
c.
d.
iris
lens
pupil
retina
Correct! The answer is (a). The iris is the thin
membrane that gives the eye its color.
Lesson 1: What is Glaucoma?
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8. Which part of the eye focuses light onto the retina?
a. iris
b. lens
c. pupil
d. retina
Correct! The answer is (b). The lens of the eye
focuses light onto the retina.
If you found these questions difficult, review the section
reading. If you are satisfied with your answers, select the
Next button to proceed.
Primary Open-Angle Glaucoma (POAG)
This section discusses primary open-angle glaucoma. To
start the reading, select the Next button below. Once you
have completed the reading, continue to the section
review.
Although several types of glaucoma exist, the most
common one is POAG. This form of glaucoma takes its
name from the shape and size of the angle between the
cornea and the iris. The term primary means occurring
without a known reason. This section describes the
Lesson 1: What is Glaucoma?
12
progression and risk factors of POAG. During this
discussion, you may refer to the previous section reading
to review the parts of the eye and their functions.
POAG is an eye disease that causes damage to the optic
nerve. How does this occur? Recall that the ciliary body
produces a fluid called aqueous humor, which fills the
posterior and anterior chambers. The aqueous humor then
leaves the eye primarily by passing through the trabecular
meshwork to the Schlemm’s canal. If the production and
outflow of the aqueous humor is balanced, the intraocular
pressure (IOP) remains normal.
Sometimes, however, the drainage of the aqueous humor
from the eye is reduced due to changes in the trabecular
meshwork. The aqueous humor cannot reach the
Schlemm’s canal easily enough to be removed from the
eye. The eye is a closed compartment, so if the
accumulating aqueous humor cannot escape, the IOP will
rise. Elevated IOP is potentially dangerous. If the eye
pressure is high enough for a long time, it permanently
damages the eye, in particular, the optic nerve. Why the
optic nerve? It is the part of the eye that is most easily
damaged by the increased pressure.
Lesson 1: What is Glaucoma?
13
Damage occurs at the part of the optic nerve called the
optic disc. A normal optic disc looks like a round or slightly
oval-shaped doughnut. It has an outer rim that surrounds
a central area called the cup. With glaucoma, the rim
progressively thins and the cup increases in size. This
process is known as “cupping.” Cupping occurs as the
elevated IOP destroys the fibers of the rim of the optic
nerve.
When a sufficient number of nerve fibers have been
destroyed, irreversible and sometimes progressive vision
loss develops. The initial loss of vision is noted in the
peripheral field, which includes top, right, left, and bottom
fields of vision. The loss of peripheral vision is usually very
gradual, often taking months or years, and affected
individuals often are not aware of the vision loss until it
becomes advanced. By the time the vision loss is noticed,
many optic nerve fibers have been destroyed. The fibers
of the optic nerve do not regenerate, and vision loss is
permanent.
If the disease progresses, the field of vision continues to
narrow, resulting in “tunnel vision.” A person with tunnel
vision sees as if looking through a tube or a pipe. What is
Lesson 1: What is Glaucoma?
14
seen may be sharp and clear, but peripheral vision may be
totally lost. The following figures show a scene first as
someone with healthy eyesight sees it and then as
someone with tunnel vision may see it.
Lesson 1: What is Glaucoma?
15
Figure 1-2: Scene as Viewed with Healthy Vision
Credit: National Eye Institute, National Institutes of Health
Reference: EDS01
Figure 1-3: Scene as Viewed with Tunnel Vision
Credit: National Eye Institute, National Institutes of Health
Reference: EDS02
Lesson 1: What is Glaucoma?
16
In more advanced stages of the disease, the central, or
straight-ahead, vision deteriorates and may ultimately be
lost. Central vision is essential for reading, driving, and
recognizing people or objects. Glaucoma reaches its final
stage when all optic nerve fibers have died, resulting in
total blindness. Although loss of vision from glaucoma is
irreversible, if glaucoma is diagnosed and treated either
with medication or surgery, further loss of vision can be
slowed or halted.
POAG has no early warning signs, neither pain nor other
symptoms. In fact, vision stays seemingly normal until the
more advanced stages of the disease when most optic
nerve fibers are destroyed. Because of this, POAG is often
called the “sneak thief of sight.” Some symptoms that may
develop in the later stages of the disease, however,
include the following:

night blindness

blurred vision




decreased response to magnification
reduced peripheral vision
increased illumination requirements
inability to adjust the eyes to darkness
Lesson 1: What is Glaucoma?
17
Once detected, glaucoma usually responds well to
medical or surgical treatment, but even with proper
treatment, a small number of people with POAG may still
lose their vision. Also, because this disease is chronic, or
ongoing, anyone diagnosed with it must adhere to a
lifelong treatment plan.
Everyone has some risk of developing this form of
glaucoma. Certain factors, however, increase a person's
chances of developing POAG. These factors include the
following:

Age: POAG occurs more often in older people,
especially those over the age of 60.



Diabetes: POAG occurs more often in people with
diabetes. Also, the longer a person has diabetes, the
greater his or her risk of developing POAG.
Extreme myopia: This is extreme nearsightedness.
Family history: If you have family members,
especially immediate relatives, with POAG, you are at
a higher risk of developing this disease. Immediate
relatives include parents and siblings. Not everyone
with a family history, however, develops POAG.
Lesson 1: What is Glaucoma?
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

Ocular hypertension: This term refers to increased
IOP, the most important risk factor in predicting
whether a person will get POAG. A “glaucoma
suspect” is a person with increased IOP, but without
damage to the optic nerve and visual fields. People
with ocular hypertension must be examined regularly
so that treatment can be initiated promptly if the
diagnosis changes from “ocular hypertension” to
“POAG.”
Race: POAG is a common cause of blindness in
individuals of African origin. In fact, in the United
States, African-Americans are more likely to develop
POAG and more likely to go blind from the disease
than other ethnic groups. Moreover, AfricanAmericans often develop POAG at a younger age
than do other ethnic groups.
Risk factors are not causes of glaucoma, but they are
associated with glaucoma. Therefore, having a risk factor
does not mean that a person will with certainty develop the
disease. Doctors recommend that people at higher risk
have more frequent eye exams. For conditions that can
Lesson 1: What is Glaucoma?
19
cause glaucoma, see the section “Secondary Glaucoma”
in the next section reading of this lesson.
This section discussed the progression and risk factors of
POAG, the most common form of glaucoma. With this
disease, clogging in the Schlemm's canal causes a
buildup of aqueous humor in the eye. In turn, IOP
increases, often damaging the optic nerve. If left
untreated, POAG can result in blindness. Moreover,
because it has no early warning signs, POAG is often
called the “sneak thief of sight.”
Section Review
Review the information in this section by answering the
following true/false and multiple-choice questions. Use the
Check Answer button to get the correct answer and an
explanation.
True/False
Indicate whether the following statements are true or false.
Note that inadvertent keystrokes may change your
answers.
1. POAG is the most common form of glaucoma.
Lesson 1: What is Glaucoma?
20
Correct! The statement is true. POAG is the most
common form of glaucoma.
2. POAG takes its name from the shape and size of the
angle between the cornea and the iris.
Correct! The statement is true. POAG takes its name
from the angle between the cornea and the iris.
3. Age is the most important risk factor in predicting
whether a person will develop POAG.
Correct! The statement is false. Ocular hypertension
is the most important risk factor that makes it more
likely that an individual will develop POAG.
4. Risk factors for glaucoma are direct causes of the
disease.
Correct! The statement is false. Risk factors for
glaucoma are associated with the disease but do not
cause it.
Lesson 1: What is Glaucoma?
21
Multiple Choice
Select the best answer for each of the following items.
Note that inadvertent keystrokes may change your
answers.
5. In POAG, what does primary mean?
a. occurring due to injury
b.
c.
d.
occurring without a known reason
related to central vision
related to peripheral vision
Correct! The answer is (b). In POAG, primary means
occurring without a known reason.
6. In some people, which part of the eye is damaged by
elevated IOP?
a. optic nerve
b. ciliary body
c. sclera
d. cornea
Correct! The answer is (a). In some people, elevated
IOP can damage the optic nerve.
Lesson 1: What is Glaucoma?
22
7. Which of the following applies to POAG?
a. It shows early warning signs.
b. It occurs less often in people with diabetes.
c. It occurs more often in older people.
d. It has no relation to family history.
Correct! The answer is (c). POAG occurs more often
in older people.
8. Which field of vision does POAG affect first?
a. intraocular
b. central
c. aqueous
d.
peripheral
Correct! The answer is (d). POAG first affects
peripheral vision.
If you found these questions difficult, review the section
reading. If you are satisfied with your answers, select the
Next button to proceed.
Other Types of Glaucoma
This section discusses the progression and risk factors of
less common forms of glaucoma. They include normal-
Lesson 1: What is Glaucoma?
23
tension glaucoma, closed-angle glaucoma, congenital
glaucoma, and secondary glaucoma. To start the reading,
select the Next button below. Once you have completed
the reading, continue to the section review.
Normal-Tension Glaucoma (NTG)
With this form of glaucoma, the IOP stays within the
normal range. Nonetheless, the optic nerve and visual
field suffer damage typical of POAG. The two diseases
follow a similar course. Risk factors for NTG include a
family history of the disease and Japanese ancestry. NTG
has no definitive cause. Doctors believe it is due, in part,
to poor blood circulation in the optic nerve. A mechanical
weakness of the optic nerve is another possible cause.
This disease is also known as low-tension glaucoma or
normal pressure glaucoma.
Closed-Angle Glaucoma (CAG)
This disease is the second most common form of
glaucoma. It commonly has an abrupt onset and is a true
ocular emergency. The anatomical shape of the angle of
some eyes make those eyes susceptible to an acute rise
of eye pressure when the pupil dilates, or becomes larger.
Lesson 1: What is Glaucoma?
24
The dilation causes the iris to narrow and block the
trabecular meshwork in the angle, effectively blocking the
flow of aqueous humor from the eye. As a result, fluid can
no longer leave the eye; the sudden rise in eye pressure is
called an angle-closure glaucoma attack.
In an angle-closure attack, the IOP must be lowered as
quickly as possible to prevent damage to the eye. Without
treatment, blindness can result in a matter of hours.
Therefore, it bears repeating: CAG is a medical
emergency requiring prompt treatment.
People with anatomically narrow angles are susceptible to
a CAG attack whenever the pupils dilate, such as when
entering a dark room. Drugs that dilate the pupil can also
trigger an attack. These include some antidepressants,
cold medications, and antihistamines, as well as some
medications to treat nausea. The pupil normally dilates
when a person is excited or anxious, so an acute
glaucoma attack may occur during times of stress.
Most people develop CAG without any warning signs prior
to an attack. Symptoms of an attack of CAG include a
combination of the following:
Lesson 1: What is Glaucoma?
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





sudden onset of blurred vision
redness of the eye
severe eye pain
halos around lights
severe headache
nausea

vomiting
Not all people with CAG experience an acute attack.
Instead, some people have minor attacks that end on their
own when the pupil constricts. These attacks may have
very mild symptoms that many people ignore. Other
people have multiple minor attacks over a long period of
time that lead to the development of chronic angle-closure
glaucoma. In this case, the iris gradually blocks the
outflow of aqueous humor through the trabecular
meshwork. At the same time, adhesions, or scar tissue,
form between these two structures. The IOP rises when a
significant amount of scarring has occurred, that is,
enough to block the drainage angle. In this case,
treatment can prevent an acute attack, but the chronic
form of the disease can persist and require lifelong
treatment.
Lesson 1: What is Glaucoma?
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The following are risk factors for CAG:

ages 40 and older, but it can occur at younger ages

Asian descent

Inuit descent
(Note that Inuit refers to the Eskimo people of North
America and Greenland.)



family history
farsightedness
presence of a narrow angle
Recall that risk factors are associated with glaucoma but
do not cause it. People with risk factors do not necessarily
develop the disease. They should, however, have a
complete eye exam at least every year or more frequently
if suggested by their doctor.
Finally, CAG can be secondary (occurring after a previous
illness or eye injury). This disease is also known as acute
glaucoma or angle-closure glaucoma.
Congenital Glaucoma
This rare form of glaucoma occurs in infants and young
children. The disease is commonly diagnosed within the
first year of life. Infants may have the following symptoms:
Lesson 1: What is Glaucoma?
27
abnormal sensitivity to light, enlargement of the eye,
cloudy cornea, and excessive tearing. Congenital
glaucoma is the result of abnormal development of the
trabecular meshwork during the prenatal period. The
resulting structural defects cause slow drainage, resulting
in high IOP. As in other forms of glaucoma, the optic nerve
is damaged. Surgery, however, when done promptly, can
correct the structural defects and thereby preserve a
child’s vision.
Genetics usually plays a role in this type of glaucoma. In
fact, most cases are inherited. A viral infection (rubella) in
the mother during pregnancy is also a risk factor. People
between the ages of 3 and 30 can develop a similar, but
sometimes less serious, form of the disease called
juvenile glaucoma.
Secondary Glaucoma
Secondary glaucoma may be mild or severe. It may also
be either open- or closed-angle glaucoma. It can result
from other ocular conditions, including the following:

eye surgery

eye injuries (trauma)
Lesson 1: What is Glaucoma?
28



eye tumors, both benign and malignant
eye inflammation
advanced cataracts
Glaucoma develops when these conditions cause a
mechanical disruption or physical change in the aqueous
drainage system. Trauma to the eye may include a blunt
trauma, chemical or thermal burn, or penetrating injury.
Glaucoma as a result of trauma can develop immediately
or commonly, months or years later.
Also, using steroids or cortisone for longer than a short
period of time may increase eye pressure. If not treated,
the elevated IOP may lead to glaucoma and optic nerve
damage. Steroid eyedrops can cause the IOP to rise.
Therefore, it is essential that doctors monitor people taking
this form of medication. Elevated IOP can also occur with
the use of oral steroids. Moreover, people who use steroid
inhalers to control asthma may also develop elevated IOP.
Note, however, that these cases are more likely to occur
when the dosage is high and is taken for an extended
period, but some people will develop elevated IOP if low
doses of steroids are taken over a long period of time.
Lesson 1: What is Glaucoma?
29
Secondary Open-Angle Glaucoma
Two of the most common forms of secondary open-angle
glaucoma are “pigmentary” and “pseudoexfoliative.”
Pigmentary glaucoma may be diagnosed in younger
adults, between the ages of 20 and 50. In those who are
affected, very small pieces of pigment separate from the
iris and are carried by the aqueous humor to the
trabecular meshwork where they accumulate and obstruct
the flow of aqueous humor from the eye. The IOP then
increases, possibly damaging the optic nerve. Many
people with this glaucoma experience transient episodes
of blurred vision and mild eye pain after exercising. Most
people however, have no early symptoms. Most often, it is
diagnosed after a routine eye exam that detected an
elevation of IOP and pigmentation loss from the iris.
Pigmentary glaucoma has several risk factors. It is more
common in men than in women and in people who are
nearsighted. People with pigment dispersion syndrome, in
which pigment is lost from the iris, are more likely to
develop this type of glaucoma.
Lesson 1: What is Glaucoma?
30
With pseudoexfoliative glaucoma, a whitish material
accumulates on the surface of the lens of the eye. As the
iris moves, this material is rubbed off the lens, and
pigment also falls off the back of the iris. Both materials
accumulate on the trabecular meshwork and obstruct the
overflow of aqueous humor from the eye. The IOP then
increases, sometimes to very high levels, thereby
damaging the optic nerve. This type of glaucoma may
appear in only one eye, or it may develop in one eye long
before the other.
This form of glaucoma has several risk factors. It is more
common among people of European descent. It is also
more common in older adults, people over the age of 50.
Secondary Closed-Angle Glaucoma
Several forms of secondary closed-angle glaucoma exist.
Iridocorneal endothelial (ICE) syndrome is one of them.
With this syndrome, adhesions form where the iris and
cornea are near each other in the angle of the eye.
Outflow of aqueous humor is blocked, which causes
elevation of IOP. Distortion of the iris and pupil, as well as
swelling of the cornea, are noted upon physical
Lesson 1: What is Glaucoma?
31
examination of the eye. The syndrome is usually present
in only one eye. It is also more likely to occur in people
between the ages of 30 and 50. As in other forms of
glaucoma, people affected by ICE may have no
symptoms. Any type of glaucoma may result in optic nerve
damage and blindness. Moreover, if an acute glaucoma
attack occurs, it is a medical emergency that requires
immediate care to prevent rapid, permanent vision loss.
Neovascular glaucoma is another form of secondary
closed-angle glaucoma. In this disease, blood vessels
grow into the angle of the eye and interfere with the
function of the trabecular meshwork. Neovascular
glaucoma may produce no early symptoms, but many
people ultimately experience a chronically red, painful eye.
In addition, this glaucoma is usually very difficult to control.
It is also associated with other disorders such as diabetes
and poor circulation in the eye. As with other forms of
glaucoma, this form of glaucoma can lead to blindness,
and in its acute form, it is a medical emergency.
This section discussed the progression and risk factors of
less common forms of glaucoma. They include NTG,
CAG, congenital glaucoma, and secondary glaucoma.
Lesson 1: What is Glaucoma?
32
Like POAG, these forms of the disease can result in
blindness. To protect vision, doctors recommend regular
eye exams, which are discussed in Lesson 2.
Section Review
Indicate whether the following statements are true or false.
Note that inadvertent keystrokes may change your
answers.
1. Closed-angle glaucoma (CAG) results in a medical
emergency.
Correct! The statement is true. CAG often results in a
medical emergency.
2. Asian descent is a risk factor for CAG.
Correct! The statement is true. Asian descent is a risk
factor for CAG.
3. Congenital glaucoma results from a structural defect
in the iris.
Correct! The statement is false. Congenital glaucoma
results from a structural defect in the trabecular
meshwork.
Lesson 1: What is Glaucoma?
33
4. Scars block the trabecular meshwork in neovascular
glaucoma.
Correct! The statement is false. Blood vessels block
the trabecular meshwork in neovascular glaucoma,
whereas scars block this structure in glaucoma
resulting from ICE syndrome.
Multiple Choice
Select the best answer for each of the following items.
Note that inadvertent keystrokes may change your
answers.
5. Which of the following applies to normal-tension
glaucoma (NTG)?
a. It has no definitive cause.
b. It involves elevated IOP.
c. It results from exfoliation.
d. It is the most common type of glaucoma.
Correct! The answer is (a). NTG has no definitive
cause.
6. In a person with CAG, when might an acute glaucoma
attack occur?
Lesson 1: What is Glaucoma?
34
a.
b.
c.
d.
when the pupil constricts
when the pupil dilates
when the angle is open
when the IOP is normal
Correct! The answer is (b). In a person with CAG, an
acute glaucoma attack might occur when the pupil
dilates.
7. Which of the following is a risk factor for CAG?
a. wide drainage angles
b. narrow drainage angles
c. an enlarged optic nerve
d.
an enlarged ciliary body
Correct! The answer is (b). Narrow drainage angles
are a risk factor for CAG.
8. Which of the following applies to pseudoexfoliative
glaucoma?
a. It is more common in children and young adults.
b.
c.
d.
It is more common in people of Asian descent.
Whitish material accumulates on the lens of the
eye.
Whitish material accumulates on the ciliary body.
Lesson 1: What is Glaucoma?
35
Correct! The answer is (c). With pseudoexfoliative
glaucoma, whitish material accumulates on the lens of
the eye.
If you found these questions difficult, review the section
reading. If you are satisfied with your answers, select the
Next button to proceed.
Summary
This lesson described some basic parts of the human eye,
as well as their functions. It also discussed the
progression and risk factors of POAG, the most common
form of glaucoma. Moreover, this lesson discussed the
progression and risk factors of some less common forms
of glaucoma. They include normal-tension, closed-angle,
congenital, and secondary glaucoma.
Lesson 1: What is Glaucoma?
36